Patent GB-545010-A (GB)
Title: Improvements in and relating to photo-electric controlled machines
IPC: G05B19/12
Filed: 1940-10-09
Abstract: 545,010. Selective control. TOMPKIN, A. P., and HEARN, A. Oct. 9, 1940, No. 12813. [Class 40 (i)] [Also in Group XL] Successive operations of machine tools such as lathes, and boring, milling, planing and grinding machines are controlled automatically by means of a selector circuit system in conjunction with a photo-electric device controlled by an obturating device such as a film with a series of opaque parts. As shown in plan by Fig. 7, a capstan lathe of the semiautomatic type is provided with a doubleacting hydraulic cylinder 179 for actuating the turret slide, a double-acting hydraulic cylinder 180 for actuating the cross slide, and a single-acting hydraulic cylinder 181 for operating the spring-controlled bar feed lever 182. These cylinders are commanded by solenoid operated valves 173.... 177 controlled by the photo-electric apparatus 185, which has a shaft 97 geared by a pinion 188 to a rack 187 adjustably clamped to the turret slide, and a shaft 95 geared by bevel gearing 192 to a shaft 191 geared by a pinion 190 to a rack 189 adjustably clamped to the cross slide. The photo-electric control apparatus shown in plan in Fig. 2 has a main shaft for driving the control' film 14. The shaft 26 can be driven in several ways according to the manner in which the control apparatus is to be used or according to the functions to be performed ; by a hand wheel 99 for various adjustments and at various stages in' the preparation of. the control film; or by a motor 53 in a forward direction through a clutch device 60, or in a backward direction through a clutch device 71 ; or by the shaft 95 always in the forward direction through a clutch device 73 or a clutch device 74 according- to the direction of rotation of the shaft 95 ; or finally by the shaft 97 through a clutch device 75. The several clutch devices are connected to the shaft 26 by bevel gears and are commanded by solenoids 65, 67, 85, 86, 87. A solenoid 100 is also provided for controlling the switch 158 in the circuit of the solenoid 177, Figs. 5 and 7. The shaft 26 drives the film sprocket 29 through a clutch 27, 28. For adjustment purposes, the clutch member 27 fast with the shaft 26 has a notch 134, Fig. 1, adapted to be engaged by a screw 133, on a fixed bracket; and the clutch member 28 is rotatably adjustable in relation to the film sprocket 29 by means of a screw 135 also on the fixed-bracket 133 and co-operating with the' lower edge of a segmental notch in the clutch member 28, which, after adjustment, is clamped to the film sprocket by a knurled nut 30. The film 14 is driven by the sprocket 29 in a forward direction from a spool 50 to a spool 43 and on its way travels through a film gate 13. As shown, an'auxiliary film sprocket 34 is provided on the other side of the film gate and chain and belt gearing is provided to ensure the simultaneous rotation of the film sprockets and spools. The photo-electric device comprises a.lamp 6 with 'a reflecting prism 10, Fig. 3, adapted to throw light down through the film gate 13 to another reflecting prism 20 which throws the light on a photo-electric cell 1 connected to an amplifier 2 for controlling a relay 4. The film is pressed up in the gate by a plate 15 under the influence of springs 19. The plate 15 has a slot 16 opposite two slits 11, 12 on the upper side of the gate for the passage of the light. These slits can be covered or uncovered by lids 22, 24, according to the manner in which the control apparatus is to be used. The lid 22 is hand operated and the lid 24 is controlled by the armature of a solenoid 23. The switches in the circuit system shown in Fig. 5 include a main switch 172 for the solenoid operated valves 173 ... 177, and another main switch 120 for the control apparatus. The main switch 120 comprises three ganged switches 121, 122, 123 and has four positions, an "off" position 124, a position 125 for hand operation and film indexing, a position 126 for film setting, and a position 127 for automatic control. There are also a single-pole switch 128 for operating relay 23 when film indexing, and a change-over single pole-switch 129 for connecting with contact 130 for actuating selector 108, 109 by solenoid 107 or with contact'131 for energizing the selected relays or solenoids. In addition, there are a switch 111 controlled by a centrifugal device for closing the circuit of the mains transformer 101 when the motor 53 is running during automatic control and film setting operations, and a set of safety switches 113, 115, 118, 119 in series in the circuit of, the transformer secondary 103, which supplies the various solenoids with current through a rectifier 104, 105. The switch 113 is opened by a relay 112 if the current in the circuit of the lamp 6 fails, the switch 115 is opened by a relay 114 if the amplifying valve 2 is inoperative; and the switches 118, 119 are opened by spring-controlled bell-cranks 116, 117, Fig. 2, if the control film breaks. The successive operations of the machine tool are determined by the passage of groups of opaque spots 205 ... 216, Fig. 10, on the film 14 through the gate 13, Fig. 1 causing successive obturations of the light resulting in successive operations of the relay 4, Fig. 5, by the amplifier 2 of the photo-electric cell 1. Each time the relay 4 is de-energized and energized its armature 137 closes and breaks contact 139 thereby energizing and de-energizing solenoid 107 which causes ganged selector switches 108, 109 to rotate one step. The selector switch 108 determines the nature of the successive operations to be performed, according to the manner its successive alternate contacts 140 are connected to the various operating solenoids. When the relay 4 is energized its armature closes contact 138 and this energizes the particular solenoid or solenoids then in circuit through the selector switch 108. The other selector switch 109 is like the selector switch 108, but is connected to lamps which indicate the corresponding positions of the selector switch 108 when the corresponding circuits are operative.